1,7-Dimethylguanosine formation in tRNA enzymatic methylation.

Data are reported showing that 1,7-dimethylguanosine is formed in tRNA enzymatic methylation and that the kidney extract exhibits a higher activity respect to the liver enzyme extract. In terms of relative percentages the amount of 1,7-dimethylguanosine produced by the kidney enzyme extract was three times higher than that produced by the liver extract. The possible importance of 1,7-dimethylguanosine in connection to chemical cancerogenesis by alkylating agents and to the aberrant increase of tRNA methylases activity in tumor tissues is advanced.